Air-pressure gauge



April 9, 1929. A. HALLSTEAD AIR PRESSURE GAUGE Filed Sept. 22, 1925 l 1HETA/12,2...

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Patented Apri. 9, 1929.

UNETE STATES PATENT OFFICE.

LEON ARTHUR HALLSTFAD, OF BUFFALO, NEW YORK,` ASSIGNOR TO KORECT AIR.METER CORPORATION, OF BUFFALO, NEW YORK, A CORPORATION F NEW YORK.

AIR-PRESSURE GAUGE.

Application filed cptember 22, 1925. Serial No. 57,933.

My invention relates to improvements in air pressure gauges of the typeshown in my patent application tiled May 27, 1925, Serial Number 83,280,and the object of the invention is to construct a device Whiehwvillaccurately gauge the air pressure ot low pressure balloon tires, andalso ot standard tires. t further object et the invention is to providemeans for preventing excessive movement ot the gauge With the consequentdistortion et its mechanism whenl it is subjected to high air pressuresas are used in pneumatic truck tires.

A still further object of the invention is to provide supplementalresilient means for assisting the movement ot the gauge when low airpressures such as are used in balloon tires are being registered.

My invention consists of an air pressure gauge constructed and arrangedall as here` inatter more particularly described and illustrated in theaccompanying drawing in which:

Fig. l is a longitudinal, sectional view through a fragmentary portionot the gauge casing and nozzle showing a sectional vievv oli' the gaugetherein in the inoperative posi tion. Y

Fig. 2 is a similar view to Figure 1, the gauge nozzle not being shown,the air pressure gauge being shown in airegistering position.

Fig. 3 is a similar View to Figure 2 shoW- ing the air pressure gauge atits highest registration point, the valve tor admitting air theretobeing closed.

Fig. 4t is a plan vievv of the `gauge Vcasing showing the graduated slotthrough which the movable sleeve of the gauge is visible.

Fig. 5 is a vertical cross sectional view through the line 5--5 Figure1, and

Fig. (5 is a cross sectional view through the line (if-6 Figure 1. l

Like characters of reference indicate corresponding parts 'in thediilerent views.

1 is a portion of the gauge casing provided in its outer end With thecircular recess or chamber 2, the outer end ot which is adapted toreceive the shouldered bushing 3 i which is preferably threadedthereinto. 1 is the outer end ot the rotatable nozzle which is turnedover at right angles to the main portion and provided at its outer endwith an orifice 5 adapted to receive the plunger 6 which is designed. toopen the automobile tire valve in the `usual manner when the nozzle isapplied thereto, the plunger `G being resilient/ly held in position bymeans of the spiral spring 7. The rotatable portion i is provided on itsinner end with a reduced portion 8 adapted to be inserted into theoriice E) of the bushing 3 and held in engage menttherewith by lock nuts1() and 1.1 Which are threaded onto the projecting endet the portion 8.12 is passage passing from the outer end ot the nozzle to the recess 2.

A circular passage 13, opening into the recess 2 is providedin thecasing 1 and adapted to receive the air pressure gauge which I shall newdescribe. The outer end of the passage 13 which communicates withtheorifiee 2 is threaded and receives a threaded bushing 1d Which has areduced shank 15 extending from its inner tace Which hasa slightlyreduced portion 16, and 17 is a passage-Way extending through thereduced portion 16 opening into an enlarged passage-Way 18 which extendsthrough the shank 15, the outer end of the passage 18 entering acircular recess 19 provided in the face of the bushing 16. 2() is asleeve of slightly smaller diameter than the passage 18 and adapted toslide therein, such sleeve being internally threaded and receiving thethreaded plug 21 which has a reduced inner portion -22 of the samediameter as the reduced portion 15. `The shank 16 en the bushing 111- isadapted to receive one end of a rubber sleeve 23, the `other end oit`such sleeve being drawn over and sealed by a plug 2d the face et Whichabuts the face of the portion 22 on the plug 21.

25 is a spiral spring which constitutes a flexible, metallic coveringfor the rubber sleeve 23, its ends encircling and secured to therespective portions 15 and 22. 26 is a spiral spring of slightly lessdiameter than the passage-Way 13 and adapted to encircle the springcovering 25 ot the rubber sleeve 23, heilig inserted between the innertace of the bushing 111 and the sleeve 20, the end ot the spring beingattached to the bushing. 27 isa longitudinal slot in one end of thepassage 13 through Whichthe sleeve 2O can be seen, and 28 is a graduatedscale on the tace et' the easing in proximity to the slot.

A valve 29 having a contact face 30 of rubber or like` material ispositioned Within the recess 19 in the tace of the bushing 1d isprovided with a centrally positioned valve stem 31 `which extendsinwardly through the passageways 13 and 17 into the rubber sleeve 23almost extending to the inner face of the plug 24 when the valve is invthe inoperative position. 32- is a tube secured tothe inner face of theplug 24 surrounding the valve rod 31 and extending forwardly in l thesleeve 23 into proximity with the inner yface of the portion 17 when thevalve is in the inoperative posi tion.'Y The free end of the valve stem31 is provided with an enlarged head 33 which issecured thereto andadapted to come in leontactwith the turned in end 31 of the tube 32 whenthe valve is extended to its limit as illustrated'in Figure 3. 35 is aspiral springV encircling the valve stem 31 and inserted into thepassageway 18 extend-V ing between the face 3() ot the valve and theshoulder constituted at the juncture ot' the passage-way 18 andtheentrance .to the red uced passage-way 17, such 'spring being normallyadapted to keep the valve normally open to permit air enteringthe gauge.

p2 would have'rno inlet for The operation of my device is as follows;'When the nozzlel portion -is applied to the tire valve (not shown)theair pressure lfrom thev source otair supply enters the recess orchamber 2, then t rough the passage 12,'and orifice 5 to the tire valve.Then such airi'pressureis shut ol' externally of the device by means ofa control valve (not shown as it forms no part of the present invention)andrassuming that the nozzle portion 4 is still applied to the tirevalve with the' plunger '6 depressing the tire'valve stem Ythe air inthetire'will flow back through the orifice 5, passage 12,'recess 2, recess197, passages 18 and 17 into the rubber sleeve 23,

through"V the tube 32 and impinges `on the Vface Vof th'eplug 24,causing the'elongation of such sleeve 23 with a consequent movement 'ofthe sleeve 20'and the air pressure in the tire is read byobservinfr therelative position of the end of the seeve 20 with respect to thegraduations on the scale 28.

' 'Thev above appliesin toto where the device er than the springcovering 25 of 4the rubber sleeve 23 it will be held ink slightcompression between the inner face of the bushing 1,4 and thesleeve 20,the end of the sleeve 20y registeringzero on the scalev 28. Then air isadmittedto the gauge under low pressure Vas used 'inlballoon tires itwillbe appreciated that the air pressure alone would not be A'sutlicientto yelongate therubber sleeve 23 and spring 25 and move the sleeve 2O asufiicient distance to registerthe correct air pressure admitted to thegauge on the scale. 23. The provision of the spring 26 which acts in thecapacity ot a booster spring prevents any possibility o an inaccuratereading being given as it assists the air pressure in moving the sleeve2() to the correct reading position. lVhcn the gauge is used indetermining the greater air pressure in standard tires the air pressurewill be sullicieut in itself to elongate the rubber sleeve 23 and spring25 and move the sleeve 20 to thc correct reading position. It will bcsccn in this case that as the sleeve 2() moves along the passage. 13that tl e, spiral spring 26 will reach its maximum expansion and becomeinolurative, whereupon any further movement of the sleeve 2() causes itto move out'y of engagement with the spring 26, this further movementdepending, ot course, entirely upon the air pressure in the rubbersleeve 23.

It has been found that in using gauges of the standard type inconjunction with air line nozzles that they are apt to become distortedand inaccurate when the nozzle is used for intiating truck tires whichcarry a high air pressure as such air pressure would enter the'gaugesubjecting it'- to a strain and actuating it beyond the limit of itsmovement. For eliminating this occurrence and preventing undue strainsupon my gauge I provide the valve 29 which is operated in the followingmanner and cuts oil' the entry of air into the gauge when a suiiieient,predetermined pressure has been reached. As the rubber sleeve 23 iselongated under the infiuence of the air pressure the plug 24 in its endwill move rearwardly carrying with it the tuhe 32 which is secured toits inner face, the headed valve stem 31 sliding in the tube. vWhen thesleeve 23 reaches its predetermined limit of expansion it will be seenthat the head 33 on the valve stem 31 will come in contact with theturned in portion 34 on the outer end of the tube 32 and the valve stem31 will he drawn rearwardly compressing the spring 35 under theinfluence of the forward movement of the tube, bringing the face 20 ofthe valve 29 into contact with the inner face of the recess 19 andcutting off any further admittance of air into the gauge. `When thenozzle is removed from the tire Valve the air pressure in thepassage-way 12 and recess 2 fill, of course,l immediately drop with theconsequent reduction of pressure upon the face of the valve 29 whichwill permit it to move outwardly under the influence of the springs 35and 31 against the air pressure in the sleeve, the air exhausting fromthe sleeve 23 and the gauge returning to its normal inoperative positionas shown in Figure 1.

From the above description of my device it will be apparent that I haveconstructed an air pressure gauge which will accurately record airpressures in `either' balloon or standard tires. Furthermore I have pronvided means for preventing the distortion of the gauge when high airpressures are admitted thereto.

lily gauge is particularly applicable for use in air line lnozzles atautomobile service stations Where motorists expect to ascertain thecorrect air pressure in their tires irrespective of Whether they are ofthe standard or balloon type and which it is also permissible to use anozzle in which my gauge is incorporated for inflating truck tires to ahigh air pressure.

l/Vhat I claim as my invention is l. A fluid. pressure gauge comprisinga casing, fluid pressure indicating means movable in the casing underthe influence of the `fluid pressure, and independent means in thecasing acting in conjunction with vthe fluid pressure for engaging andactuating the fluid pressure indicating means in the initial part of itsmovement.

2. A fluid pressure gauge comprising a casing, fluid pressure indicatingmeans movable in the casing under the influence of the fluid pressure,independent means in the casing acting in conjunction With the fluidpressure for engaging and actuating the fluid indicating means in theinitial part of its movement when low pressures are being,` registered,and means 'whereby the fluid pressure indicating means moves out ofengagement from the independent means and is solely actuated by thefluid pressure during the latter part of its movement When higher fluidpressures are being registered.

A fluid pressure gauge comprising a casing, fluid pressure indicatingmeans movable in the casing under the influence of the fluid pressure,and independent resilient means in the casing acting in conjunction withthe fluid pressure for engaging and actuating; the fluid pressureindicating means.

Il. A fluid pressure gauge comprisinga casing, fluid pressure.indicating means movable in the casing under the influence of the fluidpressure, resilient means in the easing engaging the fluid pressureindicatingmeans and tending to retain it in its non-indicating position,and a second resilient means enraging the fluid pressure indicatingmeans and adapted in conjunction with the fluid pressure to overcome theresistance to movement of the fluid pressure indicating means under theinfluence of the firstanentioned resilient retaining means.

5. il fluid pressure gauge comprising a casing, fluid pressureindicating means movable in the casing under the influence of the fluidpressure, an expandible chamber into which the fluid pressure isadmitted to actuate the fluid pressure indicating means and meansactuated by the movement of the eX- pandible chamber for cutting off thefurther admittance of fluid thereinto when said chamber has reached apredetermined expansion point.

G. A fluid pressure gauge comprising; a casing, fluid pressureindicating` means movablein the casing under the influence of the fluidpressure, a receptacle into which the fluid pressure is admitted toactuate the fluid pressure indicating; means, resilient means forcontrolling,Y the movement of the fluid pressure indicating,v meansunder the influence of the fluid pressure,`and means actuated vby thefluid pressure for cutting off' the further admittance of fluid. to thereceptacle for limiting the movement of the fluid pressure indicatingmeans When a predetermined pressure is recorded.

7. A fluid pressure gauge comprising a casing, fluid pressureindicating;- means 1nov able in the casing under the influence of thefluid pressure, an expandible fluid receiving receptacle in the casing;adapted to engage and actuate the fluid pressure indicatingmeans, avalve for controlling the admittance of fluid to the expandiblereceptacle, and means whereby the expansion of the receptacle closes thevalve when the fluid pressure has expanded the receptacle apredetermined degree.

8; A fluid pressure gauge comprising a casing, fluid pressure indicatingmeans movable in the casing` under the influence of the fluid pressure,independent resilient means in the casing,- engaging the fluid pressureindicating means and tending,` to retain it in its iioirindicatingposition, an expandible fluid pressure receiving' receptacle adapted toengage aud actuate the fluid pressure indicating means, a valve forcontrolling,- the admittance of fluid to the expandiblc receptacle andmeans for closimq` the valve when the fluid pressure :indicating meanshas reached. the limit of a predetermined movement..

9. A fluid pressure gauge comprising a casing, fluid pressureindicatingf means movable in the casing under the influence of the fluidpressure, a receptacle into which fluid `is admitted to actuate thefluid pressure incheating means, a spring` in the casing for engagging;and tending to actuate the fluid pressure indicating means, a secondspring in the casing tending` to retain the fluid pressure indicatingmeans in its non-indicating position, the second spring being adapted toexert a greater pressure upon the fluid pressure indicating means thanthe first-mentioned spring so that the fluid pressure in dicating` meansremains in its noneindicating means when only under the influence of thetwo springs and means whereby fluid pressure is admitted. to the fluidreceiving receptacle and assists, the first-mentioned spring inovercoming the resistance of the second-mentioned spring and moving thellO 4f y f 1,708,887

uidpressure indicating means to a position indicating the pressure offluid admitted to the receptacle.

10. A fluid pressure gauge comprising a casing, fluid pressureindicating means movable in the casing under the influence of the fluidpressure, an expandibie fluid receiving chamber in the easing into whichfluid is admitted, the expansion 0f such chamber actuating the Huidpressure indieating means, resilient means for keeping the expandiblechamber in its non-expanded position, and the fluid pressure indicatingmeans in its non-indicating posit-ion, contracted resilient meanstending` t0 actualite the fluid pressure indicating means, and meanswhereby fluid is admitted to the expandible chamber whereby the chamberis expanded and the fluid pressure indicating means actuated so that itis moved out of engagement with the contracted resilient means when thelimit of expansion of such resilient means is reached.

LEON ARTHUR HALLSTEAD.

